You could start by getting the results from the database in the correct order. Let's say you want the table to be sorted by "Model" by default. Your SQL-statement will need to be:

$sql = "SELECT * FROM $table ORDER BY Model ASC";

Furthermore, after outputting the results in the correct order to begin with, according to the documentation at https://github.com/filamentgroup/tablesaw you need to put data-tablesaw-sortable-default-col in the column you want to be sorted by default.